1. Field of the Invention
The present disclosure relates to an application device and an image forming system.
2. Description of the Related Art
In inkjet recording systems, there is disclosed in the related art an example of a technique to apply a treatment liquid for aggregating ink immediately before ink droplets land on a sheet of paper of a recording medium in order to improve image quality.
There is also known in the related art another example of the technique to apply such a treatment liquid on an entire surface of a sheet using rollers. FIG. 12 depicts a configuration example of an application unit as a treatment liquid application device (hereinafter also referred simply to as an “application device”) configured to apply a treatment liquid using such rollers. In FIG. 12, W indicates a recording medium such as paper, 90 represents an application unit, 91 represents a container, L represents a liquid such as a treatment liquid, 92 represents a squeeze roller, 93 represents an application roller, and 94 represents a pressure roller 94. In this example, the treatment liquid is scooped by rotations of the squeeze roller 92 driven by a motor. The treatment liquid scooped by the squeeze roller 92 is partially scraped by a nip between the application roller 93 wrapped by an elastic member such as rubber and the squeeze roller 92, and the remaining liquid is thinly and uniformly spread over the application roller 93. The treatment liquid spread on the application roller 93 is transferred on a sheet sandwiched by an application nip formed between the pressure roller 94 and the application roller 93 (see Patent Document 1).
The elastic member wrapped around the application roller 93 may be quickly deteriorated when the application roller 93 retains in contact with the squeeze roller 92 or the pressure roller 94. The positions of the application roller 93, the squeeze roller 92 and the pressure roller 94 may be adjusted to allow the application roller 93 to be in contact with the squeeze, roller 92 and the pressure roller 94 only for applying the liquid, and be separated from the squeeze roller 92 and the pressure roller 94 while not applying the liquid.